Age Calculator
Asking yourself "how old am I, exactly?" This free age calculator turns your date of birth into your precise age in years, months, and days — plus total days lived, the weekday you were born, and a live countdown to your next birthday. Everything updates instantly as you pick a date, and your birth date never leaves your browser.
Enter your date of birth
Your results
| Detail | Value |
|---|---|
| Total days lived | — |
| Total weeks | — |
| Born on | — |
| Next birthday | — |
| Days until next birthday | — |
How to use this calculator
Pick your date of birth with the date picker — the calculator opens with January 1, 2000 so you can see how it works. Your exact age updates automatically the moment you change the date, and you can press Calculate at any time to re-run it. Your age is always measured as of today.
The headline number is your calendar age in years, months, and days. Below it you'll find the totals — days lived and full weeks — the weekday you were born, and your next birthday with a live days-until countdown, plus a progress bar showing how far through your current year of age you are.
How it works
Years are found by subtracting your birth year from the current year, then subtracting one more if your birthday hasn't happened yet this year. The leftover months and days come from calendar borrowing: if today's day-of-month is smaller than your birth day-of-month, we borrow the number of days in the previous month; if the month count goes negative, we borrow 12 months from the year. So someone born on March 31 measures April 30 as exactly 0 years, 1 month, 0 days — never a negative number.
Dates are parsed as local calendar dates (new Date(year, month, day)), never as UTC, which avoids the classic off-by-one error where a time-zone shift moves your birth date into the wrong day. Total days and the birthday countdown are computed from UTC midnight timestamps, so daylight saving time can never add or remove a day. Born on February 29? The countdown points to February 28 in non-leap years, and your calendar age flips as the calendar falls — on March 1.
Frequently asked questions
How do I calculate my exact age?
Subtract your birth year from the current year, then subtract one more year if your birthday has not happened yet this year. For the extra detail, borrow months and days the way a calendar does: this calculator turns the remainder into whole months and days, so you get an answer like 26 years, 2 months, 3 days instead of just 26.
Why do age calculators sometimes show different results?
The classic cause is an off-by-one date bug. In JavaScript, new Date("2000-01-01") parses as UTC midnight, which your time zone then shifts into the previous day or the next. This page parses birth dates in your local time instead, and counts total days from midnight timestamps, so you get the same correct answer no matter your time zone.
How many days old am I?
Enter your date of birth and the calculator shows your total days lived — the exact number of day boundaries between your birth date and today. Because one year is 365 or 366 days, total days is the most precise single number for saying how old you are.
What if I was born on February 29?
You still turn one year older every year. For the next-birthday countdown this calculator uses February 28 in non-leap years, a common convention, while your calendar age increments the way the calendar naturally falls — on March 1 in non-leap years.
How do you calculate the days until my next birthday?
Your birth month and day are mapped onto this year. If that date has already passed, we use next year's instead, then count the days between the two midnights. The count uses UTC midnight timestamps, so a daylight saving change can never add or remove a day.